Apparatus and Method for Calculating Characteristics of Battery

ABSTRACT

The present invention relates to an apparatus and a method capable of calculating insulation resistances and parasitic capacitances of a battery outside the battery. In the present invention, when a positive electrode connector and a negative electrode connector are coupled to a positive electrode terminal and a negative electrode terminal of the battery, respectively, and a ground connector is coupled to a case of the battery, even though the battery is positioned inside a chamber in order to perform a temperature test or the like of the battery, the insulation resistances and the parasitic capacitances of the battery may be calculated without needing to move the battery to the outside of the chamber. Accordingly, the insulation resistances and the parasitic capacitances of the battery may be conveniently calculated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Pat. Application No.17/482,637, filed Sep. 23, 2021, which claims priority to Korean PatentApplication No. 10-2020-0123505 filed Sep. 24, 2020, the disclosures ofwhich are hereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The following disclosure relates to an apparatus and a method forcalculating characteristics of a battery, and more particularly, to anapparatus and a method capable of calculating insulation resistances andparasitic capacitances of a battery outside the battery.

Description of Related Art

In an electric vehicle, a hybrid vehicle, or the like, that uses abattery as a power source, insulation resistances of a battery are veryimportant because they inform a user that a ground fault has occurred.The insulation resistances of the battery include a positive electrodeinsulation resistance between a positive electrode terminal and a ground(e.g., a battery case) of the battery and a negative electrodeinsulation resistance between a negative electrode terminal and theground of the battery. The positive electrode insulation resistance andthe negative electrode insulation resistance have infinite values whenthe ground fault has not occurred, but have finite values when theground fault has occurred.

FIG. 1A is a diagram illustrating a form of measuring a positiveelectrode insulation resistance of a battery by using a DCR meter, andFIG. 1B is a diagram illustrating a form of measuring a negativeelectrode insulation resistance of the battery by using the DCR meter.As illustrated in FIGS. 1A and 1B, conventionally, the DCR meter wasused to measure the insulation resistances of the battery 1.

When insulation between a positive electrode terminal 10 of the battery1 and the case of the battery 1 is broken, a positive electrodeinsulation resistor 12 exists, and when insulation between the negativeelectrode terminal 20 of the battery 1 and the case of the battery 1 isbroken, a negative electrode insulation resistor 22 exists.

Conventionally, in order to measure an insulation resistance of thepositive electrode insulation resistor 12 of the battery 1, the DCRmeter was manually coupled to the positive electrode terminal 10 of thebattery 1 and the case of the battery 1 as illustrated in FIG. 1A. Atthis time, the DCR meter applied a voltage between the positiveelectrode terminal 10 and the case, and measured the insulationresistance of the positive electrode insulation resistor 12 by dividingthe applied voltage by a current flowing through the positive electrodeterminal 10 and the case.

In addition, conventionally, in order to measure an insulationresistance of the negative electrode insulation resistor 22 of thebattery 1, the DCR meter was manually coupled to the negative electrodeterminal 20 of the battery 1 and the case of the battery 1 asillustrated in FIG. 1B. At this time, the DCR meter applied a voltagebetween the negative electrode terminal 20 and the case, and measuredthe insulation resistance of the negative electrode insulation resistor22 by dividing the applied voltage by a current flowing through thenegative electrode terminal 20 and the case.

As described above, in a conventional manner of measuring the insulationresistances, a separate voltage for measuring the insulation resistancesshould be manually applied to the battery 1, and thus, the user cannotbut be exposed to a risk of an electric shock due to a high voltageapplied to the battery 1 as it is.

In addition, in order to measure the insulation resistances of thebattery 1 while performing a temperature test or the like of the battery1 in a chamber (not illustrated), the user should move the battery 1positioned in the chamber to the outside of the chamber, measure theinsulation resistances of the battery 1, and put the battery 1 againinto the chamber when the measurement of the insulation resistancesends. That is, the conventional manner of measuring the insulationresistances of the battery 1 has a problem that a measurement process iscumbersome.

Meanwhile, due to a structural problem of the battery 1, a positiveelectrode parasitic capacitor 14 coupled to the positive electrodeinsulation resistor 12 in parallel and a negative electrode parasiticcapacitor 24 coupled to the negative electrode insulation resistor 22 inparallel inevitably exist. The larger the positive electrode parasiticcapacitance Cp of the positive electrode parasitic capacitor 14 and thenegative electrode parasitic capacitance Cn of the negative electrodeparasitic capacitor 24, the longer the time required for calculating theinsulation resistances of the battery 1. That is, only when the positiveelectrode parasitic capacitance Cp of the positive electrode parasiticcapacitor 14 and the negative electrode parasitic capacitance Cn of thenegative electrode parasitic capacitor 24 are accurately measured, thetime required for calculating the insulation resistances of the battery1 may also be accurately known.

FIG. 2A is a diagram illustrating a form of measuring a positiveelectrode parasitic capacitance of a battery by using an LCR meter, andFIG. 2B is a diagram illustrating a form of measuring a negativeelectrode parasitic capacitance of the battery by using the LCR meter.As illustrated in FIGS. 2A and 2B, conventionally, the LCR meter wasused to measure the parasitic capacitances of the battery 1.

More specifically, conventionally, in order to measure the positiveelectrode parasitic capacitance of the battery 1, the LCR meter wasmanually coupled to the positive electrode terminal 10 of the battery 1and the case of the battery 1 as illustrated in FIG. 2A. In addition,conventionally, in order to measure the negative electrode parasiticcapacitance of the battery 1, the LCR meter was manually coupled to thenegative electrode terminal 20 of the battery 1 and the case of thebattery 1 as illustrated in FIG. 2B.

In the conventional manner of measuring the parasitic capacitances asdescribed above, the LCR meter is affected by a voltage of the battery1, and measurement accuracy is thus poor.

When the voltage of the battery 1 exceeds an allowable voltagespecification of the LCR meter, there is a problem that the measurementitself is not properly performed.

In addition, as described above, in order to measure the parasiticcapacitances of the battery 1 while performing a temperature test or thelike of the battery 1 in the chamber, the user should move the battery 1positioned in the chamber to the outside of the chamber, measure theparasitic capacitances of the battery 1, and put the battery 1 againinto the chamber when the measurement of the parasitic capacitancesends. That is, the conventional manner of measuring the parasiticcapacitances of the battery 1 has a problem that a measurement processis cumbersome.

Meanwhile, in Patent Document 1, A Y-capacitor installed between adirect current (DC) link stage and a chassis ground is added to aninsulation resistance calculation model to derive an equation of stateto which an extended Kalman filter may be applied, and an insulationresistance of a battery is then measured by using the equation of state.

[RELATED ART DOCUMENT] [Patent Document]

(Patent Document 1) Korean Patent Laid-Open Publication No. 2013-0127828

SUMMARY OF THE INVENTION

An embodiment of the present invention is directed to providing anapparatus and a method capable of simultaneously and accuratelycalculating a positive electrode insulation resistance and a negativeelectrode insulation resistance of a battery even when both positiveelectrode insulation and negative electrode insulation of the batteryare broken.

Another embodiment of the present invention is directed to providing anapparatus and a method capable of conveniently measuring insulationresistances and parasitic capacitances of a battery even when thebattery is positioned in a chamber in order to perform a temperaturetest or the like of the battery.

Still another embodiment of the present invention is directed toproviding an apparatus and a method capable of automatically andconveniently measuring insulation resistances and parasitic capacitancesbeyond a conventional manner of manually measuring the insulationresistances and the parasitic capacitances.

Yet still another embodiment of the present invention is directed toproviding an apparatus and a method capable of measuring insulationresistances of a battery in a safer manner beyond a conventional mannerof applying a specific voltage to the battery in order to measure theinsulation resistances of the battery.

In one general aspect, an apparatus for calculating characteristics of abattery includes: a positive electrode connector 110 coupled to apositive electrode terminal 10 of the battery 1; a negative electrodeconnector 120 coupled to a negative electrode terminal 20 of the battery1; a ground connector 130 coupled to a case 30 of the battery 1; a firstresistor 211 having one end coupled to the positive electrode connector110; a second resistor 212 having one end coupled to the negativeelectrode connector 120; a first switch 310 having one end coupled tothe other end of the first resistor 211 and the other end coupled to theother end of the second resistor 212; a first analog-digital converter(ADC) 410 coupled to the other end of the second resistor 212; a thirdresistor 213 having one end coupled to the positive electrode connector110 and one end of the first resistor 211; a fourth resistor 214 havingone end coupled to the ground connector 130; a second switch 320 havingone end coupled to the other end of the third resistor 213 and the otherend coupled to the other end of the fourth resistor 214; a fifthresistor 215 having one end coupled to the negative electrode connector120 and one end of the second resistor 212; a sixth resistor 216 havingone end coupled to the ground connector 130 and one end of the fourthresistor 214; a third switch 330 having one end coupled to the other endof the fifth resistor 215 and the other end coupled to the other end ofthe sixth resistor 216; a second ADC 420 coupled to the other end of thefourth resistor 214 and the other end of the sixth resistor 216; and acontrol unit 600 controlling turn-on/off of the first switch 310, thesecond switch 320, and the third switch 330 and calculating insulationresistances of the battery 1 through values each output from the firstADC 410 and the second ADC 420.

The apparatus for calculating characteristics of a battery may furtherinclude: a first amplifier resistor 510 having one end coupled to theother end of the sixth resistor 216; a second amplifier resistor 520having one end coupled to the other end of the first amplifier resistor510; and an operational amplifier 500 including an inverting inputterminal coupled to the other end of the first amplifier resistor 510and one end of the second amplifier resistor 520, a non-inverting inputterminal coupled to the ground connector 130, one end of the fourthresistor 214, and one end of the sixth resistor 216, and an outputterminal coupled to the other end of the second amplifier resistor 520and the second ADC 420.

The control unit 600 may control only the first switch 310 to be turnedon to obtain a value output from the first ADC 410 in a state in whichonly the first switch 310 is turned on, and may calculate a voltage ofthe battery 1 through the value output from the first ADC 410 in thestate in which only the first switch 310 is turned on and calculate theinsulation resistances of the battery 1 by using the voltage of thebattery 1.

In addition, the control unit 600 may control only the second switch 320to be turned on to obtain a value output from the second ADC 420 in astate in which only the second switch 320 is turned on, may control onlythe third switch 330 to be turned on to obtain a value output from thesecond ADC 420 in a state in which only the third switch 330 is turnedon, and may calculate the insulation resistances of the battery 1 byfurther using the value output from the second ADC 420 in the state inwhich only the second switch 320 is turned on and the value output fromthe second ADC 420 in the state in which only the third switch 330 isturned on.

The apparatus for calculating characteristics of a battery may furtherinclude: a seventh resistor 217 having one end coupled to the positiveelectrode connector 110, one end of the first resistor 211, and one endof the third resistor 213; an eighth resistor 218 having one end coupledto the negative electrode connector 120, one end of the second resistor212, and one end of the fifth resistor 215; and a fourth switch 340having one end coupled to the other end of the seventh resistor 217 andthe other end of the eighth resistor 218 and the other end coupled tothe ground connector 130, one end of the fourth resistor 214, and oneend of the sixth resistor 216, wherein the control unit 600 additionallycontrols turn-on/off of the fourth switch 340, and calculates parasiticcapacitances of the battery 1 through the voltage of the battery 1, theinsulation resistances of the battery 1, and the value output from thesecond ADC 420.

Here, the control unit 600 may control only the fourth switch 340 to beturned on and then control the second switch 320 to be turned on toobtain a value output from the second ADC 420 in a state in which onlythe second switch 320 and the fourth switch 340 are turned on, and maycalculate a positive electrode parasitic capacitance of the battery 1 byusing the value output from the second ADC 420 in the state in whichonly the second switch 320 and the fourth switch 340 are turned on.

Alternatively, the control unit 600 may control only the fourth switch340 to be turned on and then control the third switch 330 to be turnedon to obtain a value output from the second ADC 420 in a state in whichonly the third switch 330 and the fourth switch 340 are turned on, andmay calculate a negative electrode parasitic capacitance of the battery1 by using the value output from the second ADC 420 in the state inwhich only the third switch 330 and the fourth switch 340 are turned on.

In another general aspect, a method for calculating characteristics of abattery by using the apparatus for calculating characteristics of abattery described above includes: controlling only the first switch 310to be turned on; obtaining a value output from the first ADC 410 in astate in which only the first switch 310 is turned on; calculating avoltage of the battery 1 through the value output from the first ADC 410in the state in which only the first switch 310 is turned on;controlling only the second switch 320 to be turned on; obtaining avalue output from the second ADC 420 in a state in which only the secondswitch 320 is turned on; controlling only the third switch 330 to beturned on; obtaining a value output from the second ADC 420 in a statein which only the third switch 330 is turned on; and calculatinginsulation resistances of the battery 1 by using the voltage of thebattery 1, the value output from the second ADC 420 in the state inwhich only the second switch 320 is turned on, and the value output fromthe second ADC 420 in the state in which only the third switch 330 isturned on.

Here, the apparatus for calculating characteristics of a battery mayfurther include: a seventh resistor 217 having one end coupled to thepositive electrode connector 110, one end of the first resistor 211, andone end of the third resistor 213; an eighth resistor 218 having one endcoupled to the negative electrode connector 120, one end of the secondresistor 212, and one end of the fifth resistor 215; and a fourth switch340 having one end coupled to the other end of the seventh resistor 217and the other end of the eighth resistor 218 and the other end coupledto the ground connector 130, one end of the fourth resistor 214, and oneend of the sixth resistor 216, and the method for calculatingcharacteristics of a battery may further include, after the calculatingof the insulation resistances of the battery 1: controlling only thefourth switch 340 to be turned on; controlling the second switch 320 tobe turned on in a state in which the fourth switch 340 is turned on;obtaining a value output from the second ADC 420 in a state in whichonly the second switch 320 and the fourth switch 340 are turned on; andcalculating a positive electrode parasitic capacitance of the battery 1by using the voltage of the battery 1, the insulation resistances of thebattery 1, and the value output from the second ADC 420 in the state inwhich only the second switch 320 and the fourth switch 340 are turnedon.

Alternatively, the apparatus for calculating characteristics of abattery may further include: a seventh resistor 217 having one endcoupled to the positive electrode connector 110, one end of the firstresistor 211, and one end of the third resistor 213; an eighth resistor218 having one end coupled to the negative electrode connector 120, oneend of the second resistor 212, and one end of the fifth resistor 215;and a fourth switch 340 having one end coupled to the other end of theseventh resistor 217 and the other end of the eighth resistor 218 andthe other end coupled to the ground connector 130, one end of the fourthresistor 214, and one end of the sixth resistor 216, and the method forcalculating characteristics of a battery may further include, after thecalculating of the insulation resistances of the battery 1: controllingonly the fourth switch 340 to be turned on; controlling the third switch330 to be turned on in a state in which the fourth switch 340 is turnedon; obtaining a value output from the second ADC 420 in a state in whichonly the third switch 330 and the fourth switch 340 are turned on; andcalculating a negative electrode parasitic capacitance of the battery 1by using the voltage of the battery 1, the insulation resistances of thebattery 1, and the value output from the second ADC 420 in the state inwhich only the third switch 330 and the fourth switch 340 are turned on.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a diagram illustrating a form of measuring a positiveelectrode insulation resistance of a battery by using a DCR meter.

FIG. 1B is a diagram illustrating a form of measuring a negativeelectrode insulation resistance of the battery by using the DCR meter.

FIG. 2A is a diagram illustrating a form of measuring a positiveelectrode parasitic capacitance of a battery by using an LCR meter.

FIG. 2B is a diagram illustrating a form of measuring a negativeelectrode parasitic capacitance of the battery by using the LCR meter.

FIG. 3 is a diagram illustrating an apparatus for calculatingcharacteristics of a battery according to the present invention.

FIG. 4 is a flowchart illustrating a method for calculatingcharacteristics of a battery using the apparatus for calculatingcharacteristics of a battery according to FIG. 3 .

FIG. 5A is a diagram illustrating a current path when only a firstswitch is controlled to be turned on in the apparatus for calculatingcharacteristics of a battery of FIG. 3 .

FIG. 5B is a diagram illustrating a current path when only a secondswitch is controlled to be turned on in the apparatus for calculatingcharacteristics of a battery of FIG. 3 .

FIG. 5C is a diagram illustrating a current path when only a thirdswitch is controlled to be turned on in the apparatus for calculatingcharacteristics of a battery of FIG. 3 .

FIG. 6A is a diagram illustrating a current path when only the secondswitch and a fourth switch are controlled to be turned on in theapparatus for calculating characteristics of a battery of FIG. 3 .

FIG. 6B is a diagram illustrating a current path when only the thirdswitch and the fourth switch are controlled to be turned on in theapparatus for calculating characteristics of a battery of FIG. 3 .

DETAILED DESCRIPTION OF MAIN ELEMENTS

1: battery 10: positive electrode terminal 20: negative electrodeterminal 30: case 100: connector 110: positive electrodeconnector 120:negative electrode connector 130: ground connector 211: first resistor212: second resistor 213: third resistor 214: fourth resistor 215: fifthresistor 216: sixth resistor 217: seventh resistor 218: eighth resistor310: first switch 320: second switch 330: third switch 340: fourthswitch 410: first ADC 420: second ADC 500: operational amplifier 510:first amplifier resistor 520: second amplifier resistor 600: controlunit 1000: apparatus for calculating characteristics of battery

DESCRIPTION OF THE INVENTION

Hereinafter, an apparatus and a method for calculating characteristicsof a battery according to the present invention will be described indetail with reference to the accompanying drawings. The accompanyingdrawings are provided only by way of example in order to sufficientlytransfer the technical spirit of the present invention to those skilledin the art, and the present invention is not limited to the accompanyingdrawing provided below, but may be implemented in other forms. In thepresent specification, the term ‘or’ refers to a combination of aplurality of related items or any one of a plurality of related items.

FIG. 3 is a diagram illustrating an apparatus for calculatingcharacteristics of a battery according to the present invention. Asillustrated in FIG. 3 , an apparatus 1000 for calculatingcharacteristics of a battery according to the present invention mayinclude a connector 100 electrically coupled to a battery 1.

In the present invention, the battery 1, which is a target ofcharacteristic calculation, may be installed in an electric vehicle, ahybrid vehicle, or the like. In addition, the battery 1 may be a batterymodule including a plurality of battery cells or a battery packincluding a plurality of battery modules.

The battery 1 includes a positive electrode terminal 10 and a negativeelectrode terminal 20, and includes a case 30 surrounding the pluralityof battery cells or the plurality of battery modules. Here, the case 30corresponds to a floating ground of the apparatus 1000 for calculatingcharacteristics of a battery.

The characteristics of the battery 1 to be calculated in the presentinvention are a positive electrode insulation resistance Risop and anegative electrode insulation resistance Rison of the battery, and areadditionally a positive electrode parasitic capacitance Cp or a negativeelectrode parasitic capacitance Cn of the battery.

As described above, when insulation between the positive electrodeterminal 10 of the battery 1 and the case 30 of the battery 1 is broken,a positive electrode insulation resistor 12 exists, and when insulationbetween the negative electrode terminal 20 of the battery 1 and the case30 of the battery 1 is broken, a negative electrode insulation resistor22 exists. In addition, due to a structural problem of the battery 1, apositive electrode parasitic capacitor 14 coupled to the positiveelectrode insulation resistor 12 in parallel and a negative electrodeparasitic capacitor 24 coupled to the negative electrode insulationresistor 22 in parallel inevitably exist.

The connector 100 includes a positive electrode connector 110, anegative electrode connector 120, and a ground connector 130. Here, thepositive electrode connector 110 is coupled to the positive electrodeterminal 10 of the battery 1, the negative electrode connector 120 iscoupled to the negative electrode terminal 20 of the battery 1, and theground connector 130 is coupled to the case 30 of the battery 1. In thepresent invention, when the positive electrode connector 110 and thenegative electrode connector 120 are coupled to the positive electrodeterminal 10 and the negative electrode terminal 20 of the battery 1,respectively, and the ground connector 130 is coupled to the case 30 ofthe battery 1, even though the battery 1 is positioned inside a chamber(not illustrated) in order to perform a temperature test or the like ofthe battery 1, characteristics of the battery 1 may be calculatedwithout needing to move the battery 1 to the outside of the chamber, andthus, the characteristics of the battery 1 may be convenientlycalculated.

The apparatus 1000 for calculating characteristics of a batteryaccording to the present invention includes a first resistor 211, asecond resistor 212, a first switch 310, and a first analog-digitalconverter (ADC) 410.

The first resistor 211 has one end coupled to the positive electrodeconnector 110, and the second resistor 212 has one end coupled to thenegative electrode connector 120. The first switch 310 has one endcoupled to the other end of the first resistor 211 and the other endcoupled to the other end of the second resistor 212. Here, the firstswitch 310 may be formed of only a solid state relay (SSR) or be formedof a combination of a digital isolator and a solid state relay. Thefirst ADC 410 is coupled to the other end of the second resistor 212.The first resistor 211, the second resistor 212, the first switch 310,and the first ADC 410 are used to calculate a voltage Vb of the battery1 as described later.

The apparatus 1000 for calculating characteristics of a batteryaccording to the present invention includes a third resistor 213, afourth resistor 214, a fifth resistor 215, a sixth resistor 216, asecond switch 320, a third switch 330, and a second ADC 420.

The third resistor 213 has one end coupled to the positive electrodeconnector 110 and one end of the first resistor 211, and the fourthresistor 214 has one end coupled to the ground connector 130. The fifthresistor 215 has one end coupled to the negative electrode connector 120and one end of the second resistor 212, and the sixth resistor 216 hasone end coupled to the ground connector 130 and one end of the fourthresistor 214.

The second switch 320 has one end coupled to the other end of the thirdresistor 213 and the other end coupled to the other end of the fourthresistor 214. The third switch 330 has one end coupled to the other endof the fifth resistor 215 and the other end coupled to the other end ofthe sixth resistor 216. Here, each of the second switch 320 and thethird switch 330 may be formed of a solid state relay. The second ADC420 is coupled to the other end of the fourth resistor 214 and the otherend of the sixth resistor 216.

The third resistor 213, the fourth resistor 214, the second switch 320,and the second ADC 420 are used to calculate a positive electrodeinsulation voltage Visop and the positive electrode parasiticcapacitance Cp. In addition, the fifth resistor 215, the sixth resistor216, the third switch 330, and the second ADC 420 are used to calculatea negative electrode insulation voltage Vison and the negative electrodeparasitic capacitance Cn.

The apparatus 1000 for calculating characteristics of a batteryaccording to the present invention may include a first amplifierresistor 510, a second amplifier resistor 520, and an operationalamplifier 500.

The first amplifier resistor 510 has one end coupled to the other end ofthe sixth resistor 216, and the second amplifier resistor 520 has oneend coupled to the other end of the first amplifier resistor 510.

The operational amplifier 500 includes an inverting input terminal, anon-inverting input terminal, and an output terminal. The invertinginput terminal is coupled to the other end of the first amplifierresistor 510 and one end of the second amplifier resistor 520. Thenon-inverting input terminal is coupled to the ground connector 130, oneend of the fourth resistor 214, and one end of the sixth resistor 216.The output terminal is coupled to the other end of the second amplifierresistor 520 and the second ADC 420. The operational amplifier 500serves to invert and amplify a voltage applied across the sixth resistor216, and then transfer the inverted and amplified voltage to the secondADC 420.

The apparatus 1000 for calculating characteristics of a batteryaccording to the present invention may include a seventh resistor 217,an eighth resistor 218, and a fourth switch 340.

The seventh resistor 217 has one end coupled to the positive electrodeconnector 110, one end of the first resistor 211, and one end of thethird resistor 213. The eighth resistor 218 has one end coupled to thenegative electrode connector 120, one end of the second resistor 212,and one end of the fifth resistor 215.

The fourth switch 340 has one end coupled to the other end of theseventh resistor 217 and the other end of the eighth resistor 218. Inaddition, the fourth switch 340 has the other end coupled to the groundconnector 130, one end of the fourth resistor 214, and one end of thesixth resistor 216. Here, the fourth switch 340 may be formed of only asolid state relay or be formed of a combination of a digital isolatorand a solid state relay.

The seventh resistor 217, the eighth resistor 218, and the fourth switch340 are used to calculate the positive electrode parasitic capacitanceCp and the negative electrode parasitic capacitance Cn of the battery 1,together with the second ADC 420.

In addition, the apparatus 1000 for calculating characteristics of abattery according to the present invention includes a control unit 600,a first signal transfer unit 710, a second signal transfer unit 720, acommunication unit 800, a first power supply unit 910, and a secondpower supply unit 920.

The control unit 600 may control turn-on/off of the first switch 310,the second switch 320, and the third switch 330. In addition, thecontrol unit 600 may obtain values each output from the first ADC 410and the second ADC 420 when it controls the turn-on/off of the firstswitch 310, the second switch 320, and the third switch 330. Inaddition, the control unit 600 may simultaneously calculate the positiveelectrode insulation resistance Risop and the negative electrodeinsulation resistance Rison of the battery 1 through the values eachoutput from the first ADC 410 and the second ADC 420. In the presentinvention, the control unit 600 may be formed of a microcontroller unit(MCU) in order to perform the control of the switch as described above,obtainment of digital values from the ADCs, and perform arithmeticprocessing through the obtained digital values.

The first signal transfer unit 710 may transfer the value output fromthe first ADC 410 to the control unit 600, and the second signaltransfer unit 720 may transfer the value output from the second ADC 420to the control unit 600. Each of the first signal transfer unit 710 andthe second signal transfer unit 720 may be formed of a digital isolator.Alternatively, each of the first signal transfer unit 710 and the secondsignal transfer unit 720 may be formed of an opto-coupler.

The control unit 600 may additionally control turn-on/off of the fourthswitch 340. In this case, the control unit 600 may obtain a value outputfrom the second ADC 420 according to the additional turn-on/off controlof the fourth switch 340. In addition, the control unit 600 maycalculate the positive electrode parasitic capacitance Cp and thenegative electrode parasitic capacitance Cn of the battery 1 through thevoltage of the battery 1, the insulation resistances of the battery 1,and the value output from the second ADC 420.

The communication unit 800 may be communicatively coupled to anapparatus (i.e., an external apparatus) positioned outside the apparatus1000 for calculating characteristics of a battery. When thecommunication unit 800 is communicatively coupled to the externalapparatus, the communication unit 800 serves to transfer acharacteristic calculation command of the battery 1 received from theexternal apparatus to the control unit 600. To this end, thecommunication unit 800 is communicatively coupled to the control unit600 in the apparatus 1000 for calculating characteristics of a battery.Here, the characteristic calculation command of the battery 1 mayinclude one or more of a voltage calculation command of the battery 1,an insulation resistance calculation command of the battery 1, and aparasitic capacitance calculation command of the battery 1.

The communication unit 800 is also communicatively coupled to the firstpower supply unit 910 and the second power supply unit 920. When thecommunication unit 800 gives power supply commands to the first powersupply unit 910 and the second power supply unit 920, the first powersupply unit 910 supplies driving power to the first ADC 410, and thesecond power supply unit 920 supplies driving power to the second ADC420.

FIG. 4 is a flowchart illustrating a method for calculatingcharacteristics of a battery using the apparatus for calculatingcharacteristics of a battery according to FIG. 3 . Hereinafter, aspecific embodiment of calculating characteristics of a battery will bedescribed with further reference to FIG. 4 .

First, the apparatus 1000 for calculating characteristics of a batteryis in a standby state, and it is periodically determined whether or notthe communication unit 800 receives the characteristic calculationcommand of the battery 1 from the external apparatus (S10).

When the communication unit 800 does not receive the characteristiccalculation command of the battery 1 from the external apparatus, theapparatus 1000 for calculating the characteristics of the battery isstill in the standby state.

When the communication unit 800 receives the characteristic calculationcommand of the battery 1 from the external apparatus, the communicationunit 800 transfers the characteristic calculation command of the battery1 received from the external apparatus to the control unit 600. At thistime, the communication unit 800 may give power supply commands to thefirst power supply unit 910 and the second power supply unit 920.Accordingly, the first power supply unit 910 supplies driving power tothe first ADC 410, and the second power supply unit 920 supplies drivingpower to the second ADC 420.

When the control unit 600 receives the characteristic calculationcommand of the battery 1 from the communication unit 800, the controlunit 600 controls only the first switch 310 to be turned on for a presettime (e.g., A seconds) (S100).

After the step S100, the control unit 600 obtains a value Vp output fromthe first ADC 410 in a state in which only the first switch 310 isturned on (S200).

FIG. 5A is a diagram illustrating a current path when only the firstswitch is controlled to be turned on in the apparatus for calculatingcharacteristics of a battery of FIG. 3 . As illustrated in FIG. 5A, whenthe control unit 600 controls only the first switch 310 to be turned on,a current path from the positive electrode terminal 10 of the battery 1to the negative electrode terminal 20 of the battery 1 through thepositive electrode connector 110, the first resistor 211, the firstswitch 310, the second resistor 212, and the negative electrodeconnector 120 is formed. For reference, before the control unit 600controls only the first switch 310 to be turned on, that is, when theapparatus 1000 for calculating characteristics of a battery is in thestandby state, the positive electrode parasitic capacitor 14 and thenegative electrode parasitic capacitor 24 of the battery 1 are in astate in which they are already charged with voltages.

When a resistance value of the first resistor 211 is R4 and a resistancevalue of the second resistor 212 is R5, the first ADC 410 detects andoutputs a voltage value Vp as expressed in the following Equation 1. Inthe following Equation 1, the value Vp output from the first ADC 410 isobtained by the control unit 600 through the first signal transfer unit710. In the following Equation 1, Vb is a voltage of the battery 1.

Vp = Vb × R5/(R4 + R5)

After the step S200, the control unit 600 calculates the voltage Vb ofthe battery 1 through the value Vp output from the first ADC 410 in thestate in which only the first switch 310 is turned on (S300). The aboveEquation 1 may be expressed as the following Equation 2, and the controlunit 600 may calculate the voltage Vb of the battery 1 through thefollowing Equation 2.

Vb = Vp × (R4 + R5)/R5

In the present invention, the control unit 600 calculates the insulationresistances Risop and Rison of the battery 1 by using the voltage Vb ofthe battery 1 calculated as in the above Equation 2. As described above,in the conventional manner of measuring the insulation resistances, aseparate voltage for measuring the insulation resistances should bemanually applied to the battery 1, and accordingly, a user is exposed toa risk of an electric shock due to a high voltage applied to the battery1 as it is. However, according to the present invention, the voltage ofthe battery 1 is calculated and the insulation resistances Risop andRison of the battery 1 are calculated by using the calculated voltage ofthe battery 1, and thus, the user may escape from the risk of theelectric shock due to the high voltage applied to the battery 1.

After the step S300, the control unit 600 controls the first switch 310to be turned off, and controls only the second switch 320 to be turnedon for a preset time (e.g., B seconds) (S400) .

After the step S400, the control unit 600 obtains a value Visop outputfrom the second ADC 420 in a state in which only the second switch 320is turned on (S200).

FIG. 5B is a diagram illustrating a current path when only the secondswitch is controlled to be turned on in the apparatus for calculatingcharacteristics of a battery of FIG. 3 . As illustrated in FIG. 5B, whenthe control unit 600 controls only the second switch 320 to be turnedon, a series combined resistance of the third resistor 213 and thefourth resistor 214 is in parallel with the positive electrodeinsulation resistor 12 of the battery 1.

At this time, when a resistance value of the third resistor 213 is R1and a resistance value of the fourth resistor 214 is R2, the second ADC420 detects and outputs a positive electrode insulation voltage valueVisop as expressed in the following Equation 3, and the positiveelectrode insulation voltage value Visop output from the second ADC 420is obtained by the control unit 600 through the second signal transferunit 720.

Visop = Vb × [(R2 + R1)∥ Risop)]/[[(R2 + R1)∥ Riosp)] + Rison]

After the step S500, the control unit 600 controls the second switch 320to be turned off, and controls only the third switch 330 to be turned onfor a preset time (e.g., B seconds) (S600).

After the step S600, the control unit 600 obtains a value Vison outputfrom the second ADC 420 in a state in which only the third switch 330 isturned on (S700).

FIG. 5C is a diagram illustrating a current path when only the thirdswitch is controlled to be turned on in the apparatus for calculatingcharacteristics of a battery of FIG. 3 . As illustrated in FIG. 5C, whenthe control unit 600 controls only the third switch 330 to be turned on,a series combined resistance of the fifth resistor 215 and the sixthresistor 216 is basically in parallel with the negative electrodeinsulation resistor 22 of the battery 1.

Here, when the apparatus 1000 for calculating characteristics of abattery includes the first amplifier resistor 510, the second amplifierresistor 520, and the operational amplifier 500, and when a resistancevalue of the fifth resistor 215 is R1, a resistance value of the sixthresistor 216 is R2, and both resistance values of the first amplifierresistor 510 and the second amplifier resistor 520 are R3, the secondADC 420 detects and outputs a negative electrode insulation voltagevalue Vison as expressed in the following Equation 4. In addition, thenegative electrode insulation voltage value Vison output from the secondADC 420 is obtained by the control unit 600 through the second signaltransfer unit 720.

Vison = Vb × [(R2∥+R3))(+R1)∥ Rison)]/[[(R2∥R3))(+R1)∥ Rison)] + Risop]

After the step S700, the control unit 600 calculates the insulationresistances Risop and Rison of the battery 1 by using the voltage Vb ofthe battery 1, the value Visop output from the second ADC 420 in thestate in which only the second switch 320 is turned on, and the valueVison output from the second ADC 420 in the state in which the thirdswitch 330 is turned on (S800).

More specifically, the control unit 600 may calculate the positiveelectrode insulation resistance Risop and the negative electrodeinsulation resistance Rison of the battery 1 by substituting the voltageVb of the battery 1 calculated through the above Equation 2 into each ofan equation regarding Visop according to the above Equation 3 and anequation regarding Vison according to the above Equation 4 and thencombining the above Equations 3 and 4 with each other. The positiveelectrode insulation resistance Risop of the battery 1 calculated insuch a manner is expressed in the following Equation 5, and the negativeelectrode insulation resistance Rison of the battery 1 calculated insuch a manner is expressed in the following Equation 6.

$Risop = \frac{A/{B - A - \lbrack {( {A \times D \times E} )/( {E - D \times E} )} \rbrack}}{1 + \lbrack {( {A \times D} )/( {E - D \times E} )} \rbrack}$

$Rison = \frac{E/{D - E - \lbrack {( {A \times E \times B} )/( {A - A \times B} )} \rbrack}}{1 + \lbrack {( {E \times B} )/( {A - A \times B} )} \rbrack}$

In the above Equations 5 and 6, parameters A, B, D, and E are asfollows, respectively.

$\begin{array}{l}{A = {1/{( {1/{R2 + {1/{R3}}}} ) + R1}}} \\{B = ( {{Vison}/{Vb}} ) \times \lbrack {R1 + {( {R2\| {R3} )} )/( {R2\| {R3} )} )}} \rbrack} \\{D = ( {{Visop}/{Vb}} ) \times \lbrack {( {R1 + R2} )/{R2}} \rbrack} \\{E = R1 + R2}\end{array}$

Although it has been described above that steps S600 and S700 areperformed after steps S400 and S500, the order may be changed so thatsteps S600 and S700 are first performed and steps S400 and S500 are thenperformed. That is, the control unit 600 may first control only thethird switch 330 to be turned on and then obtain the value Vison outputfrom the second ADC 420 in the state in which only the third switch 330is turned on, and control only the second switch 320 to be turned on andthen obtain the value Vison output from the second ADC 420 in the statein which only the second switch 320 is turned on.

In a conventional method for measuring the insulation resistances of thebattery 1 by using the DCR meter, the insulation resistances of thebattery 1 might be measured only when any one of positive electrodeinsulation and negative electrode insulation of the battery 1 is broken.That is, in the conventional method, the insulation resistances of thebattery 1 might not be measured when both the positive electrodeinsulation and the negative electrode insulation of the battery 1 arebroken On the other hand, according to the present invention, theinsulation resistances of the battery 1 are calculated by using (forexample, combining) both of the value Visop output from the second ADC420 in the state in which only the second switch 320 is turned on andthe value Vison output from the second ADC 420 in the state in whichonly the third switch 330 is turned on, and thus, the positive electrodeinsulation resistance Risop and the negative electrode insulationresistance Rison of the battery 1 may be simultaneously calculated withhigh accuracy even when both the positive electrode insulation and thenegative electrode insulation of the battery 1 are broken.

Meanwhile, after the control unit 600 calculates the insulationresistances Risop and Rison of the battery 1 in the step S800, thecontrol unit 600 may calculate the positive electrode parasiticcapacitance Cp of the battery 1 or calculate the negative electrodeparasitic capacitance Cn of the battery 1. A method for calculating thepositive electrode parasitic capacitance Cp of the battery 1 willhereinafter be described first, but the negative electrode parasiticcapacitance Cn of the battery 1 may also be calculated first.

In order to calculate the positive electrode parasitic capacitance Cp ofthe battery 1, the control unit 600 first controls only the fourthswitch 340 to be turned on (S900).

When only the fourth switch 340 is controlled to be turned on, thecontrol unit 600 may calculate initial voltage values applied to thepositive electrode parasitic capacitor 14 and the negative electrodeparasitic capacitor 24, respectively.

More specifically, when the control unit 600 controls only the fourthswitch 340 to be turned on, the seventh resistor 217 is in parallel withthe positive electrode parasitic capacitor 14 and the eighth resistor218 is in parallel with the negative electrode parasitic capacitor 24.

Accordingly, voltages each applied to the positive electrode parasiticcapacitor 14 and the negative electrode parasitic capacitor 24 aredistributed according to a resistance value of the seventh resistor 217and a resistance value of the eighth resistor 218. When the voltage Vbof the battery 1 at a point in time when the control unit 600 controlsonly the fourth switch 340 to be turned on is 1000 V and both theresistance values of the seventh resistor 217 and the eighth resistor218 are R6, that is, are the same as each other, the voltages eachapplied to the positive electrode parasitic capacitor 14 and thenegative electrode parasitic capacitor 24 become 500 V. Here, thevoltages of 500 V correspond to the initial voltage values each appliedto the positive electrode parasitic capacitor 14 and the negativeelectrode parasitic capacitor 24.

That is, when the voltage of the battery 1 at the point in time when thecontrol unit 600 controls only the fourth switch 340 to be turned on isVb, the initial voltage value applied to the positive electrodeparasitic capacitor 14 is Vb/2 when both the resistance value of theseventh resistor 217 and the resistance value of the eighth resistor 218are R6, that is, are the same as each other. Here, the initial voltagevalue Vb/2 applied to the positive electrode parasitic capacitor 14 maybe used by the control unit 600 to calculate the positive electrodeparasitic capacitance Cp of the positive electrode parasitic capacitor14 according to Equation 11 to be described later.

In addition, when the voltage of the battery 1 at the point in time whenthe control unit 600 controls only the fourth switch 340 to be turned onis Vb, the initial voltage value applied to the negative electrodeparasitic capacitor 24 is Vb/2 when both the resistance value of theseventh resistor 217 and the resistance value of the eighth resistor 218are R6, that is, are the same as each other. Here, the initial voltagevalue Vb/2 applied to the negative electrode parasitic capacitor 24 maybe used by the control unit 600 to calculate the negative electrodeparasitic capacitance Cn of the negative electrode parasitic capacitor24 according to Equation 16 to be described later.

As described above, according to the present invention, the control unit600 controls only the fourth switch 340 to be turned on to calculate theinitial voltage values each applied to the positive electrode parasiticcapacitor 14 and the negative electrode parasitic capacitor 24, suchthat the positive electrode parasitic capacitance Cp and the negativeelectrode parasitic capacitance Cn may be calculated more stably andwith high accuracy.

After the step S900, the control unit 600 controls the second switch 320to be turned on for a preset time (i.e., for C seconds) from a to secondto a t₀+C second in a state in which only the fourth switch 340 isturned on (S1000). Here, t₀ refers to a time when the second switch 320is controlled to be turned on in the state in which only the fourthswitch 340 is turned on.

After the step S1000, the control unit 600 obtains a value Visop outputfrom the second ADC 420 for C seconds in a state in which only thesecond switch 320 and the fourth switch 340 are turned on (S1100).

FIG. 6A is a diagram illustrating a current path when only the secondswitch and the fourth switch are controlled to be turned on in theapparatus for calculating characteristics of a battery of FIG. 3 . Asillustrated in FIG. 6A, when the control unit 600 controls only thesecond switch 320 and the fourth switch 340 to be turned on, a seriescombined resistance of the third resistor 213 and the fourth resistor214 is in parallel with the seventh resistor 217, and is also inparallel with the positive electrode insulation resistor 12 of thebattery 1. In addition, the eighth resistor 218 is in parallel with thenegative electrode insulation resistor 22 of the battery 1.

At this time, when a resistance value of the third resistor 213 is R1, aresistance value of the fourth resistor 214 is R2, and each ofresistance values of the seventh resistor 217 and the eighth resistor218 is R6, the second ADC 420 detects and outputs a positive electrodeinsulation voltage value Visop(SP) as expressed in the followingEquation 7, and the positive electrode insulation voltage valueVisop(SP) output from the second ADC 420 is obtained by the control unit600 through the second signal transfer unit 720.

$\begin{array}{l}{Visop( {SP} ) = Vb( {SP} ) \times} \\{\lbrack {Risop\| {R6\| ( {R1 + R2} ) )} )} \rbrack/\lbrack {\lbrack {Riosp\| {R6} )\| ( {R1 + R2} ) )} \rbrack + ( {Rison\| {R6} )} )} \rbrack}\end{array}$

In the above Equation 7, the positive electrode insulation voltage valueVisop(SP) is a value detected and output by the second ADC 420 after atime enough for the positive electrode parasitic capacitor 14 to be nolonger discharged has elapsed (for example, after C seconds haveelapsed). In addition, in the Equation 7, Vb(SP) refers to a voltage ofthe battery 1 after a time enough for the positive electrode parasiticcapacitor 14 to be no longer discharged has elapsed (for example, afterC seconds have elapsed).

As described above, the control unit 600 obtains the value output fromthe second ADC 420 for C seconds in the state in which only the secondswitch 320 and the fourth switch 340 are turned on, and the positiveelectrode insulation voltage value Visop detected and output by thesecond ADC 420 for C seconds is a value that changes in real timeaccording to time t. Accordingly, when the above Equation 7 is expressedas the value that changes in real time according to time t, it isexpressed by the following Equation 8.

$\begin{array}{l}{Visop(t) = Vb(t) \times} \\{\lbrack {Risop\| {R6\| ( {R1 + R2} ) )} )} \rbrack/\lbrack {\lbrack {Riosp\| {R6} )\| ( {R1 + R2} ) )} \rbrack + ( {Rison\| {R6} )} )} \rbrack}\end{array}$

In addition, the above Equation 8 may be expressed as the followingEquation 9.

$\begin{array}{l}{Vb(t) = \lbrack {\lbrack {Risop\| {R6} )\| ( {R1 + R2} ) )} \rbrack + ( {Rison\| {R6} )} )} \rbrack \times} \\{{Visop(t)}/\lbrack {Risop\| {R6\| ( {R1 + R2} ) )} )} \rbrack}\end{array}$

Meanwhile, a total energy Ep generated by discharge in the positiveelectrode parasitic capacitor 14 is expressed by the following Equation10.

$Ep = {\int_{t_{0}}^{t_{0} + C}{\frac{\lbrack {Vb(t) - Vb( {SP} )} \rbrack^{2}}{RA}dt = \frac{Cp}{2}\lbrack {\frac{Vb}{2} - Vb( {SP} )} \rbrack^{2}}}$

In the above Equation 10, RA refers to a total resistance between thepositive electrode terminal 10 of the battery 1 and the case 30 of thebattery 1 in the state in which only the second switch 320 and thefourth switch 340 are turned on. Referring to FIG. 6A, when the controlunit 600 controls only the second switch 320 and the fourth switch 340to be turned on, the series combined resistance of the third resistor213 and the fourth resistor 214 is in parallel with the seventh resistor217 and is also in parallel with the positive electrode insulationresistor 12 of the battery 1, and thus, RA is Risop || R6 || (R1 +R2 +R2)

When the above Equation 10 is arranged as an equation regarding thepositive electrode parasitic capacitance Cp of the positive electrodeparasitic capacitor 14, it may be expressed as the following Equation11.

$Cp = \frac{2Ep}{\lbrack {{Vb}/{2 - Vb( {SP} )}} \rbrack^{2}}$

As can be seen from the above Equations 9 to 11, after the step S1100,the control unit 600 may calculate the positive electrode parasiticcapacitance Cp of the battery 1 by using the voltage Vb of the battery 1calculated in the step S300, the insulation resistances Risop and Risonof the battery 1 calculated in the step S800, and a value Visop(t)output from the second ADC 420 in the state in which only the secondswitch 320 and the fourth switch 340 are turned on (S1200).

Meanwhile, after the control unit 600 calculates the insulationresistances Risop and Rison of the battery 1 in the step S800, thecontrol unit 600 may calculate the negative electrode parasiticcapacitance Cn of the battery 1.

In order to calculate the negative electrode parasitic capacitance Cn ofthe battery 1, the control unit 600 first controls only the fourthswitch 340 to be turned on (S900′) .

As described above, when only the fourth switch 340 is controlled to beturned on, the control unit 600 may calculate initial voltage valuesapplied to the positive electrode parasitic capacitor 14 and thenegative electrode parasitic capacitor 24, respectively.

After the step S900′, the control unit 600 controls the third switch 330to be turned on for a preset time (i.e., for C′ seconds) from a to′second to a t₀′+C′ second in a state in which only the fourth switch 340is turned on (S1000′). Here, to′ refers to a time when the third switch330 is controlled to be turned on in the state in which only the fourthswitch 340 is turned on.

After the step S1000′, the control unit 600 obtains a value Vison outputfrom the second ADC 420 for C′ seconds in a state in which only thethird switch 330 and the fourth switch 340 are turned on (Sl 100′).

FIG. 6B is a diagram illustrating a current path when only the thirdswitch and the fourth switch are controlled to be turned on in theapparatus for calculating characteristics of a battery of FIG. 3 . Asillustrated in FIG. 6B, when the control unit 600 controls only thethird switch 330 and the fourth switch 340 to be turned on, a seriescombined resistance of the fifth resistor 215 and the sixth resistor 216is in parallel with the eighth resistor 218, and is also in parallelwith the negative electrode insulation resistor 22 of the battery 1. Inaddition, the seventh resistor 217 is in parallel with the positiveelectrode insulation resistor 12 of the battery 1.

At this time, when a resistance value of the fifth resistor 215 is R1, aresistance value of the sixth resistor 216 is R2, and each of resistancevalues of the seventh resistor 217 and the eighth resistor 218 is R6,the second ADC 420 detects and outputs a negative electrode insulationvoltage value Vison(SN) as expressed in the following Equation 12, andthe negative electrode insulation voltage value Vison(SN) output fromthe second ADC 420 is obtained by the control unit 600 through thesecond signal transfer unit 720.

$\begin{array}{l}{Vison( {SN} ) = Vb( {SN} ) \times} \\{\lbrack {Rison\| {R6\| ( {R1 + R2\| {R3} )} ) )} )} \rbrack/\lbrack {\lbrack {Rison\| {R6} )\| ( {R1 + R2\| {R3} )} ) )} \rbrack +} )} \\( ( {Risop\| {R6} )} ) \rbrack\end{array}$

In the above Equation 12, the negative electrode insulation voltagevalue Vison(SN) is a value detected and output by the second ADC 420after a time enough for the negative electrode parasitic capacitor 24 tobe no longer discharged has elapsed (for example, after C′ seconds haveelapsed). In addition, in the Equation 12, Vb(SN) refers to a voltage ofthe battery 1 after a time enough for the negative electrode parasiticcapacitor 24 to be no longer discharged has elapsed (for example, afterC′ seconds have elapsed).

As described above, the control unit 600 obtains the value output fromthe second ADC 420 for C′ seconds in the state in which only the thirdswitch 330 and the fourth switch 340 are turned on, and the negativeelectrode insulation voltage value Vison detected and output by thesecond ADC 420 for C′ seconds is a value that changes in real timeaccording to time t. Accordingly, when the above Equation 12 isexpressed as the value that changes in real time according to time t, itis expressed by the following Equation 13.

$\begin{array}{l}{Vison(t) = Vb(t) \times} \\{\lbrack {Rison\| {R6\| ( {R1 + R2\| {R3} )} ) )} )} \rbrack/\lbrack {\lbrack {Rison\| {R6} )\| ( {R1 + R2\| {R3} )} ) )} \rbrack +} )} \\( ( {Risop\| {R6} )} ) \rbrack\end{array}$

In addition, the above Equation 13 may be expressed as the followingEquation 14.

$\begin{array}{l}{Vb(t) = \lbrack {Rison\| {R6\| ( {R1 + R2\| {R3} )} ) )} )} \rbrack + ( {Risop\| {R6} )} ) \times} \\{{Vision(t)}/\lbrack \lbrack {Rison\| {R6} )\| ( {R1 + R2\| {R3} )} ) )} \rbrack )}\end{array}$

Meanwhile, a total energy En generated by discharge in the negativeelectrode parasitic capacitor 24 is expressed by the following Equation15.

$En = {\int_{t_{0}{}^{\prime}}^{t_{0}{}^{\prime} + C}{\frac{\lbrack {Vb(t) - Vb( {SN} )} \rbrack^{2}}{RB}dt = \frac{Cn}{2}\lbrack {\frac{Vb}{2} - Vb( {SN} )} \rbrack^{2}}}$

In the above Equation 15, RB refers to a total resistance between thenegative electrode terminal 20 of the battery 1 and the case 30 of thebattery 1 in the state in which only the third switch 330 and the fourthswitch 340 are turned on. Referring to FIG. 6B, when the control unit600 controls only the third switch 330 and the fourth switch 340 to beturned on, the series combined resistance of the fifth resistor 215 andthe sixth resistor 216 is in parallel with the eighth resistor 218 andis also in parallel with the negative electrode insulation resistor 22of the battery 1, and thus, RB is Rison ll R6 || (R1 + R2 || R3).

When the above Equation 15 is arranged as an equation regarding thenegative electrode parasitic capacitance Cn of the negative electrodeparasitic capacitor 24, it may be expressed as the following Equation16.

$Cn = \frac{2En}{\lbrack {{Vb}/{2 - Vb( {SN} )}} \rbrack^{2}}$

As can be seen from the above Equations 14 to 16, after the step S1100′,the control unit 600 may calculate the negative electrode parasiticcapacitance Cn of the battery 1 by using the voltage Vb of the battery 1calculated in the step S300, the insulation resistances Risop and Risonof the battery 1 calculated in the step S800, and a value Vison(t)output from the second ADC 420 in the state in which only the thirdswitch 330 and the fourth switch 340 are turned on (S1200′).

According to the present invention, the insulation resistances of thebattery are calculated by using (for example, combining) both of thevalue output from the second ADC in the state in which only the secondswitch is turned on and the value output from the second ADC in thestate in which only the third switch is turned on, and thus, thepositive electrode insulation resistance and the negative electrodeinsulation resistance of the battery may be simultaneously calculatedwith high accuracy even when both the positive electrode insulation andthe negative electrode insulation of the battery are broken.

In the present invention, the positive electrode connector and thenegative electrode connector are coupled to the positive electrodeterminal and the negative electrode terminal of the battery,respectively, and the ground connector is coupled to the case of thebattery. Accordingly, even though the battery is positioned inside thechamber in order to perform the temperature test or the like of thebattery, the insulation resistances and the parasitic capacitances ofthe battery may be calculated without needing to move the battery to theoutside of the chamber, and thus, the insulation resistances and theparasitic capacitances of the battery may be conveniently calculated.

In addition, conventionally, the insulation resistances of the batteryshould be manually measured twice by using the DCR meter, and theparasitic capacitances of the battery should be manually measured twiceby using the LCR meter. However, in the present invention, when thepositive electrode connector and the negative electrode connector arecoupled to the positive electrode terminal and the negative electrodeterminal of the battery, respectively, and the ground connector iscoupled to the case of the battery, the control unit automaticallycalculates the insulation resistances and the parasitic capacitances ofthe battery, and thus, the characteristics of the battery may beconveniently confirmed as compared with the conventional art.

According to the present invention, instead of manually applying aseparate voltage for measuring the insulation resistances to thebattery, the voltage of the battery is calculated and the insulationresistances of the battery are calculated by using the calculatedvoltage of the battery, and thus, the user may escape from the risk ofthe electric shock due to the high voltage applied to the battery.

In addition, in the conventional method of measuring the parasiticcapacitances of the battery by using the LCR meter, the LCR meter isaffected by the voltage of the battery, such that it is difficult toaccurately measure the parasitic capacitances. However, according to thepresent invention, the parasitic capacitances are calculated in a mannerof discharging a voltage already charged in the parasitic capacitors,and may thus be calculated with high accuracy.

Although the present invention has been described with reference torespective embodiments and the drawings, the present invention is notlimited to the abovementioned embodiments, and may be variously modifiedand altered from the above description by those skilled in the art towhich the present invention pertains. Therefore, the technical spirit ofthe present invention should be understood only by the claims, and allof the equivalences and equivalent modifications to the claims will beintended to fall within the scope of the technical spirit of the presentinvention.

What is claimed is:
 1. A method for calculating characteristics of abattery by using an apparatus for calculating characteristics of abattery, which apparatus includes a first switch, a first ADC, a secondswitch, a second ADC and a third switch, comprising: controlling onlythe first switch to be turned on; obtaining a value output from thefirst ADC in a state in which only the first switch is turned on;calculating a voltage of the battery through the value output from thefirst ADC in the state in which only the first switch is turned on;controlling only the second switch to be turned on; obtaining a valueoutput from the second ADC in a state in which only the second switch isturned on; controlling only the third switch to be turned on; obtaininga value output from the second ADC in a state in which only the thirdswitch is turned on; and calculating insulation resistances of thebattery by using the voltage of the battery, the value output from thesecond ADC in the state in which only the second switch is turned on,and the value output from the second ADC in the state in which only thethird switch is turned on.
 2. The method for calculating characteristicsof a battery of claim 1, wherein the apparatus for calculatingcharacteristics of a battery further includes a fourth switch, and themethod for calculating characteristics of a battery further comprises,after the calculating of the insulation resistances of the battery:controlling only the fourth switch to be turned on; controlling thesecond switch to be turned on in a state in which the fourth switch isturned on; obtaining a value output from the second ADC in a state inwhich only the second switch and the fourth switch are turned on; andcalculating a positive electrode parasitic capacitance of the battery byusing the voltage of the battery, the insulation resistances of thebattery, and the value output from the second ADC in the state in whichonly the second switch and the fourth switch are turned on.
 3. Themethod for calculating characteristics of a battery of claim 1, whereinthe apparatus for calculating characteristics of a battery furtherincludes a fourth switch, and the method for calculating characteristicsof a battery further comprises, after the calculating of the insulationresistances of the battery: controlling only the fourth switch to beturned on; controlling the third switch to be turned on in a state inwhich the fourth switch is turned on; obtaining a value output from thesecond ADC in a state in which only the third switch and the fourthswitch are turned on; and calculating a negative electrode parasiticcapacitance of the battery by using the voltage of the battery, theinsulation resistances of the battery, and the value output from thesecond ADC in the state in which only the third switch and the fourthswitch are turned on.